Cable trough

ABSTRACT

A cable trough for installing cables alongside a railway line or other right of way is described. The cable trough is constructed using longitudinally oriented reinforcing fibers coated with polymeric resin that generally aligns the reinforcing fibers with the length of the cable trough. One or more connector clips may be used to secure respective portions of the cable trough to one another. The cable trough is provided with a cover that may be removably secured to an elongate channel to protect the cables housed within the cable trough. Elbows, corners, tees, and other connectors may be provided to run the cable trough in any desired direction. A method of installing cables in a cable trough is also described.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Provisional Application Ser. No.60/404,688 filed Aug. 19, 2002, and priority to International PCTApplication Serial No. PCT/US03/25867, filed Aug. 19, 2003.

FIELD OF THE INVENTION

The present invention relates to a conduit system adapted for containingand protecting various types of wiring laid alongside, beneath, orotherwise adjacent to railroad tracks.

BACKGROUND OF THE INVENTION

Railroad lines provide an ideal location for the placement of varioustypes of cabling. Included in this group are electrical cables and othertypes of communication cabling. However, because of the nature of thematerials from which railway lines are constructed, it is inadvisable tosimply bury a cable beneath a railroad line. The pressures and abrasiveaction of the ballast used to support railway lines quickly degrade anycables buried without protection. In addition, repairs to cabling mayinterfere with the travel of trains over the railway lines.

Various types of conduit have been provided for the protection of cableslaid alongside or beneath rail lines. Examples include extruded plastic,pre-cast concrete, cast-in-place concrete, molded composite materialshaving random orientation of fiber-reinforcing strands therein, andsteel. Concrete, both pre-cast and cast-in-place, is extremely heavy andtherefore installation may be quite expensive. Extruded plastic cabletroughs, both unreinforced and reinforced with randomly oriented fiberstrands, have relatively low strengths and, accordingly, shorter lifespans and reduced ability to withstand the rigors of installationadjacent a railway lines. Cast or molded thermoplastic materials havingrandomly oriented fibers tend to be somewhat stronger than unreinforcedtypes of cabling trough, but are quite expensive. Steel cable trough canalso be quite expensive. Accordingly, there is recognized a need for acable trough for railway cabling that has high strength and islightweight and durable and yet which is inexpensive.

These and other objectives and advantages of the invention will appearmore fully from the following description, made in conjunction with theaccompanying drawings wherein like reference characters refer to thesame or similar parts throughout the several views.

SUMMARY OF THE INVENTION

The cable trough of the present invention embodies an elongate channelthat has a bottom and a pair of sidewalls that extend upwardly therefromin a generally parallel relationship with each other. A removable top isadapted to be placed onto the sidewalls and can be secured to thechannel in order to enclose cables disposed within the channel.Preferably, both the channel and the top of the cable trough are formedof a thermosetting resin having contained therein generally uniformlylongitudinally oriented reinforcing fibers. These materials arefabricated into the cable trough of the present invention, preferablyusing a pultrusion process.

Respective lengths or sections of the channel from which the cabletrough is made are connected to one another by one or more, andpreferably three, connecting clips that are secured between thesidewalls and/or bottom of the respective sections in order to connectthem to one another. The connecting clip has a central web with a firstand second edge and a pair of stringers that are connected to the firstand second edges. The stringers are spaced apart by the web and aregenerally parallel to one another. The stringers and the web togetherform a pair of diametrically opposed mouths that are adapted to clamptherein a sidewall or bottom of the channel or the cover of the cabletrough. In general, the connecting clip has an “H”-shaped cross-section.One benefit to the use of this type of connecting clip is that no toolsare required to assemble a run of the cable trough of the presentinvention.

The cable trough of the present invention is relatively simple toinstall. A method for installation of the cable trough begins withidentifying the path where the cables must be run. A first and then asecond or subsequent section of the cable trough will then be emplacedalong the path along which the cable is to run in an end-to-endrelationship. At least one of the connecting clips is installed betweenthe respective ends of each subsequent section of cable trough in orderto secure the sections to one another. Once the channel portion of thecable trough has been installed, the requisite cables are laid withinthe trough and the cable trough covers are placed onto the channelsections of the cable trough and removably secured thereto in order toprotect the cables from the exterior environment.

It is to be understood that the cable trough of the present inventionmay take many shapes and forms, including elongate straight sections,curved sections, T-connectors, and other variously shaped connectors andruns.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded cross-sectional perspective view of a typicalcable trough illustrating the relationship between the channel of thetrough and its cover;

FIGS. 2 a–2 c illustrate a T-section, a 45° bend, and a 90° bend in thecable trough, respectively;

FIG. 3 illustrates an H-clip of the type used to assemble two sectionsof cable trough of the present invention.

DETAILED DESCRIPTION

Although the disclosure hereof is detailed and exact to enable thoseskilled in the art to practice the invention, the physical embodimentsherein disclosed merely exemplify the invention which may be embodied inother specific structure. While the preferred embodiment has beendescribed, the details may be changed without departing from theinvention, which is defined by the claims. Cable trough is typicallyinstalled alongside railway lines, either above grade or below grade,depending on the application. Above-grade installations of cable troughmay be made directly on the surface of the ballast that supports arailway line, or in an elevated position where the cable trough has beensecured to, for example, the wall of a railway tunnel.

FIG. 1 illustrates a cross-section of a typical cable trough constructedand arranged according to the present invention. Note that anydimensions appearing in the figures are by way of illustration only andit is to be understood that the present invention is not limited tothose dimensions. The cable trough 10 of the present inventionessentially comprises a channel 12 having a top such as cover 14. Thechannel comprises a pair of generally vertical sidewalls 16 extendingupwardly from and secured to a bottom such as base plate 18. Each of thesidewalls 16 has on an inner surface thereof an inwardly extending lip20 that may be formed continuously along the sidewall 16 or in certainpredetermined locations as desired. The lip 20 serves as a part of aclosure mechanism that retains the cover 14 on the channel 12 once thecable trough 10 has been installed.

The cover 14 essentially comprises an elongate plate 22 that has a widthand length that are commensurate in scope with those of the channel 12.The plate 22 has a pair of channel members 24 that extend downwardlytherefrom and which engage the upper edges of the respective sidewall 16of the channel 12. Note that the channel members 24 address both sidesof the upper edge of the sidewalls 16. In FIG. 1 the cover 14 andchannel 12 are shown in their disassembled position.

When the cover 14 has been seated firmly onto the channel 12, with theupper edges of the sidewalls 16 seated within the channel members 24 ofthe cover 14, one or more connector bolts may be passed downwardlythrough the cover through countersunk bores 26 formed therein. Theconnector bolts (not shown) have a cam or other offset projectionextending from a distal end thereof such that when the connector bolt isrotated, as by screwdriver or the like, to a closed position, the cam orprojection will be positioned beneath the lip 20 of the sidewall 16.When in its closed position, the connector bolts will secure the top 14to the channel 12 to complete the cable trough 10. As can beappreciated, cabling, whether electrical, mechanical or fiber optic, islaid in the channel 16 of the cable trough 10 before the cover 14 isplaced thereon.

It should be understood that the cable trough 10 of the presentinvention is not waterproof as such. Accordingly, in order to preventthe accumulation of water and ice inside the channel 12 of the cabletrough 10, one or more drain holes 15 may be formed through the bottomof the trough to allow water to exit the channel 12.

FIGS. 2 a–2 c illustrate various types of connectors that may beinterposed between straight sections in order to run the cable trough 10around corners and to create slightly more complex networks. FIG. 2 aillustrates a simple tee 30. FIG. 2 b illustrates a 45° bend 32 and FIG.2 c illustrates a 90° bend 34. It is to be understood that theconnectors illustrated in FIGS. 2 a–2 c are exemplars only, and manymore connectors useable with the cable trough 10 of the presentinvention may be created for use therewith.

FIG. 3 is a schematic view of the cable trough 10 of the presentinvention illustrating how two sections of the cable trough 10 aresecured to one another. As can be seen in FIG. 3, successive sections ofcable trough 10 are laid end to end. One or more clips 40 are used toconnect the respective bottom surfaces 18 and sidewalls 16 of the cabletrough portions 10. The clips 40 are generally “H” shaped in profilehaving a central web 42 that connects first and second stringers 44 andmaintains them in a generally parallel relationship with one another.These stringers 44 are spaced apart or otherwise constructed andarranged to resiliently clamp the sidewalls 16 of the respective cabletrough portions therebetween. It is preferred to utilize a single clip40 for each sidewall 16 and bottom 18 in order to connect the successiveportions of cable trough 10. The assembly of the successive portions ofcable trough 10 may be achieved without the use of tools, the clampingaction of the clips 40 working in conjunction with the weight of ballasttypically placed on or around the cable trough 10 to maintain the cabletrough 10 in its assembled state.

The method of assembling cable trough 10 of the present inventioncomprises the steps of emplacing a first portion of cable trough in apredetermined position and emplacing a second portion of cable trough 10in the second predetermined position adjacent the first portion of cabletrough such that the end portions of the cable trough are adjacent oneanother. The clips 40 are attached to the end of the first portion ofcable trough 10 and the end of the second portion of cable trough isthen inserted into the remaining free ends of the clips 40 to secure thetwo portions of cable trough to one another. Note that this process isessentially the same for connecting straight portions of cable trough 10as for connecting straight portions to connectors, or connectors toconnectors. Once the portions of channel 12 have been secured to oneanother and the desired cabling has been placed therein, complementarycovers 14 are placed onto the channels 12 of the cable trough 10 andsecured thereto using connector bolts passed through countersunk bores26 in the cover 14.

In order to achieve a suitable level of strength the channels 12 of thecable trough, and preferably the connectors as well, are produced usingan extrusion method commonly referred to as pultrusion. Essentially,continuous strands of reinforcing fibers, typically glass, althoughother types of reinforcing fibers may be used, are coated or wetted witha heat-curable thermosetting polymeric resin and then pulled through aforming die. The forming die is heated so as to set and cure the resinin the desired shape. The benefit to using this pultrusion method isthat the reinforcing fibers present within the sidewall 16 and bottom 18of the channel, and also those reinforcing fibers present in the cover14, run longitudinally through these structures, thereby creating a muchmore rigid structure. The uniformly oriented reinforcing fibers in thecable trough 10 of the present invention result in greater ultimatestrength, rigidity, and lower deflections. This greater strength andrigidity enables the cable trough of the present invention to lastlonger than typical prior art cable troughs made of cast concrete ormolded or extruded thermoplastics having randomly oriented reinforcingfibers incorporated thereinto. The increased strength not only improvesthe cable trough's resistance to damage, but also results in a longeruseful life for the cable trough 10, thereby greatly reducing itseffective cost.

Given the flexible nature of the pultrusion process used to produce thecable trough 10 of the present invention, the geometry of the sidewalls16, bottom 18 and cover 14 may be easily changed. This flexibility inmanufacturing allows the cable trough 10 to be adapted for varyingsituations very rapidly and inexpensively. And, because the longitudinalorientation of the reinforcing fibers in the cable trough structures,there is a near exponential increase in the loading capacity of thecable trough 10 per unit increase in the sidewall 16 thickness. Thisfeature of the cable trough 10 allows relatively small changes in thegeometry of the trough 10 to account for large variations in the mannerin which the trough 10 may be used. This feature also allows thiscustomization to be accomplished relatively inexpensively, as littleextra material need be used to realize large increases in the strengthof the trough 10.

The foregoing is considered as illustrative only of the principles ofthe invention. Furthermore, since numerous modifications and changeswill readily occur to those skilled in the art, it is not desired tolimit the invention to the exact construction and operation shown anddescribed. While the preferred embodiment has been described, thedetails may be changed without departing from the invention, which isdefined by the claims.

1. A cable trough for containing cables comprising: an elongate channelhaving a bottom with a pair of sidewalls formed continuously along alength of the bottom and extending upwardly therefrom; a removable topbeing operatively configured to engage upper edges of the sidewalls andsecured to the channel to form an enclosed cable trough having agenerally rectangular cross-section, the channel and the top of thecable trough being formed from longitudinally oriented reinforcingfibers coated with polymeric resin; and a connecting clip having acentral web with a first edge and a second edge, a pair of stringersconnected to the first and second edges of the central web in agenerally parallel relationship with one another and spaced apart by theweb, the stringers and the web forming a pair of opposing mouths thatare constructed and arranged to receive therein at least one of asidewall, a bottom, and the top of the cable trough.
 2. The cable troughof claim 1 wherein the opposing mouths of the connecting clipresiliently secure to distinct sections of cable trough so as to connectthe distinct sections of cable trough to one another.
 3. A cable troughassembly having a first and second cable trough sections as claimed inclaim 2 where the first cable trough section is coupled to the secondcable trough section with at least one connecting clip interposedbetween the first and second cable trough sections.
 4. The cable troughof claim 1 wherein at least one of the sidewalls comprises an innersurface with an inwardly extending lip that serves as a part of aclosure mechanism.
 5. The cable trough of claim 4 wherein the inwardlyextending lip is formed continuously along the sidewall.
 6. The cabletrough of claim 4 wherein the removable top comprises a pair of channelmembers extending downward therefrom and are formed to mate with thesidewall lip as a part of the closure mechanism.
 7. The cable trough ofclaim 1 wherein the elongate channel bottom comprises a flange extendingoutward from the sidewalls so as to provide additional stability andrigidity to the cable trough.
 8. The cable trough claim 1 wherein thecable trough is formed from generally uniformly longitudinally orientedglass reinforcing fibers coated within heat-curable thermosettingpolymeric resin.
 9. The cable trough claim 1 wherein the elongatechannel comprises a substantially straight section.
 10. The cable troughclaim 1 wherein the elongate channel comprises a connector having a teeshape and operatively configured to be interposed between substantiallystraight sections.
 11. The cable trough claim 1 wherein the elongatechannel comprises a connector having a bend shape and operativelyconfigured to be interposed between substantially straight sections inorder to run the cable trough around corners.
 12. A method of installingcables in a cable trough comprising steps of: emplacing a first sectionof cable trough along a path where the cable is to be installed, thecable trough section having a first end and a second end; securing to atleast one of the ends of the first section of cable trough at least oneconnecting clip, the connecting clip comprising a pair of stringersarranged in a generally parallel relationship to one another and spacedapart by a central web and connected to the web, the stringers and theweb forming a pair of opposing mouths, the mouths being constructed andarranged to resiliently clamp therein one of the first and second endsof the cable trough; emplacing a second section of cable trough having afirst and a second end along the path where the cable is to beinstalled, one of the first and second ends of the second section ofcable trough being located adjacent one of the first or second ends ofthe first section of cable trough, the first and second sections ofcable trough being generally aligned with the cable path, the secondsection of cable trough being connected to the first section of cabletrough by means of the connector dip by sliding one of the ends of thesecond section of the cable clip into the remaining mouth of the atleast one connector clip; laying a cable within the connected sectionsof cable, trough; placing a cover over the connected sections of cabletrough; and removably securing the cover to the connected sections ofcable trough.